Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carboxylic acid or derivative thereof
Patent
1994-10-06
1996-01-23
Hampton-Hightower, P.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carboxylic acid or derivative thereof
528422, 528423, C08G 7308
Patent
active
054865921
DESCRIPTION:
BRIEF SUMMARY
FIELD OF INVENTION
This application is a 371-of-PCT/FR 94/000-37 filed Jan. 12, 1994.
The present invention relates to copolyoxadiazoles of block type of formula: ##STR2## in which: R represents an aliphatic residue, A an aromatic residue than 0.6 temperatures.
BACKGROUND OF THE INVENTION
H. Frazer (Journal of Polymer Science (A2) pp. 1137-1160 (1964)) has described the synthesis of copolyoxadiazoles by reacting diacid chloride with a dihydrazide derivative of another diacid according to the scheme (1), in sulphuric acid: ##STR3## a polyhydrazide is thus obtained, which is isolated and then heat-treated in order to obtain the cyclized oxadiazole form ##STR4##
The structure is alternating, with a unit B following a unit A.
Ueda and Sugita (Journal of Polymer Science A26, 159 (1988)) describe the synthesis of polyoxadiazoles in a single step from diacids and hydrazine sulphate in methanesulphonic acid solvent in the presence of phosphoric anhydride.
The polyoxadiazoles obtained from aromatic diacids have a high thermal stability and are materials possessing a high rigidity. However, these materials cannot in general be melted because their melting point is above 400.degree. C.
The introduction of aliphatic segments, by the use of a mixture of aromatic diacids and aliphatic diacids, leads to a reduction in the melting point of the copolyoxadiazoles. Korshak (Vysokomol Soed. B 10(8) 568 (1988) and Polymer Science of USSR 8, 883 (1966)) has prepared copolyoxadiazoles of alternating type, that is to say that the aliphatic units and the aromatic units are alternately distributed.
The melting points are as follows:
______________________________________ COPOLYMERS MELTING POINT in .degree.C.
______________________________________
6/I 180
6/T 240
10/I 100
10/T 220
______________________________________
6 and 10 denote the number of carbons in the aliphatic unit, (I) isophthalic acid and (T) terephthalic acid, the aliphatic and aromatic units are separated by the oxadiazole units ##STR5##
Only one glass transition temperature (Tg) and only one melting point are found for each copolymer.
The Korshak synthesis is effected either by reacting aliphatic dicarboxylic acid dichloroanhydrides with aromatic dicarboxylic acid dihydrazides or by reacting aromatic dicarboxylic acid dichloroanhydrides with aliphatic dicarboxylic acid dihydrazides.
These polyoxadiazoles and copolyoxadiazoles containing alternating aliphatic and aromatic units are either crystalline or amorphous. They do not posses the properties of elastomer materials.
SUMMARY OF THE INVENTION
Copolyoxadiazoles of block type have now been found having two glass transition temperatures and having elastomeric properties.
DETAILED DESCRIPTION OF THE INVENTION
The invention more precisely relates to copolyoxadiazoles of block type of formula: ##STR6## in which: R represents an aliphatic residue, A an aromatic residue 0.2 g per deciliter at 30.degree. C.) in deciliters per gram is greater than 0.6, and having two glass transition temperatures.
For simplicity, the following terms will be used in reference to: ##STR7## and the aromatic oxadiazole blocks ##STR8## Various transitions are thus observed on differential thermal analysis, corresponding to the actual transitions Tm and Tg (Tm denotes the melting point) for each of the two phases. This distinguishes them from the copolymers of alternating type, which have only one glass transition temperature (Tg) which is approximately equivalent to the weight average of the Tg's of the two phases A and B.
n and n' are preferably between 3 and 20.
The residue R represents a linear or branched aliphatic chain.
This phase A advantageously has a glass transition temperature (TgA) between -50.degree. and +50.degree. C. and a melting point (TmA) between +50.degree. and +150.degree. C.
R may represent a residue having from 2 to 20 carbon atoms.
R may also represent several aliphatic residues, that is to say that several and various residues R may be within one and the same block.
With regard to the residues
REFERENCES:
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patent: 4487921 (1984-12-01), Stephens
Frazier et al., "Aliphatic polyhydrazides: a new low temperature solution polymerization", J. Polymer Sci,: Part A, vol. 2, No. 3, pp. 1137-1145, Mar. 1964.
Idemitsu Kosan KK, Derwent WPI, Access No. 88-180126/26, abstract of JP-A-63 118 331, "High molecular weight polyoxidiazole preparation by condensing dicarboxylic acid and hydrazine sulphate in presence of phosphorus pentoxide and methanesulphonic acid", 1988.
Ueda et al., "Synthesis of poly(1,3,4-oxadiazole)s by direct polycondendsation of dicarboxylic acids with hydrazine sulfate using phosphorus pentoxide/methanesulfonic acid as condensing agent and solvent", J. Polymer Sci,: Part A, vol. 26, No. 1, pp. 159-166, Jan. 1988.
Brifaud Thierry
Sage Jean-Marc
Elf Atochem S.A.
Hampton-Hightower P.
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